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U05AB Invalid Data Received From Engine Disconnect Clutch

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modePossible

In parallel hybrids the engine disconnect clutch sits between engine crankshaft and electric machine; opened, it lets the car drive electrically with the engine off, closed, it starts the engine or adds its torque. Ford's patents describe the clutch being prestroked so it is filled with pressure before an engine start is requested, and being advanced before the hydraulic pump spins down. Where the clutch has its own smart actuator or position sensor on the network, U05AB records that its reports of position, pressure or state arrive but are implausible. No manufacturer documents U05AB or its partner U02AA publicly. Without trustworthy clutch data the hybrid controller can no longer blend engine starts safely, so electric driving, engine start-stop or hybrid assist are typically restricted.

Likely causes

Clutch actuator electronics or position sensor faulty

Actuator and hybrid controller software not matched or adaptation lost

Wiring or connector at the transmission bell housing damaged

Symptoms

Hybrid system warning and check engine light
Electric driving unavailable, engine runs continuously
Jerky engine starts

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€100–2,500

Time0.5–6 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

engine disconnect clutch actuator

Related codes

U02AA

References: patents.google.com, patents.google.com, law.cornell.edu.